Version 3.x of Apple's Xcode IDE.
Xcode 3.0 was released with Mac OS X v10.5 "Leopard". Notable changes since 2.1 include[16] the DTrace debugging tool (now called Instruments), refactoring support, context-sensitive documentation, and Objective-C 2.0 with garbage collection. It also supports Project Snapshots, which provide a basic form of version control; Message Bubbles, which show build errors debug values alongside code; and building four-architecture fat binaries (32 and 64-bit Intel and PowerPC).